Aircraft bank and turn control system



June 1 4, 1949. c. a. NYMAN 2,472,918

AIRCRAFT BANK AND TURN CONTROL SYSTEM Filed Aug. 23, 1944 IN VEN TOR.

2. CARL a. NYMAN ATTORNEY Patented June 14, 1949 AIRCRAFT BANK AND TURN CONTROL SYSTEM Carl G. Nyman, Shaker Heights, Ohio, assignor,

by mesne assignments, to Jack & Heintz Precision Industries, Inc., Cleveland, Ohio, a corporation of Delaware Application August 23, 1944, Serial No. 550,841

9 Claims. (Cl. 24479) This invention relates in general to automatic pilots and more particularly to bank and turn control devices.

One of the primary objects of the invention is to provide an improved bank and turn control device wherein two separate hand controls may be employed for separate aileron and rudder trim and a single gyro and single hand control utilized to initiate and effect a combined rudder and aileron control for a predetermined rate of airplane turn.

To this and other ends it is proposed for example in connection with the conventional pneumatic-hydraulic automatic pilot aileron and rudder systems to employ a single gyro which is mounted in a gimbal support constrained to one axis of movement. Conventional air pick-oifs are employed for the rudder and aileron air relays but they are so mounted as to be jointly operated by the gyro gimbal as it moves in either direction relative to the gyro spin axis. After the rudder and aileron are separately trimmed the coordinated turn knob is set which resiliently biases the gyro gimbal in either direction. Suitable separate difierential gear trains are employed to permit individual aileron and rudder trim, the proper operation of the rudder and aileron follow-up systems and the combined operation of the rudder and aileron air pick-offs by the coordinated turn knob.

With the foregoing and other objects in view, the invention resides in the combination of parts and in the details of construction hereinafter set forth in the following specification and appended claims, certain embodiments thereof being illustrated in the accompanying drawings, in which:

Figure 1 is a schematic illustration of the airplane rudder and ailerons and the pneumatichydraulic control systems therefor, the constrained gyro and the rudder and aileron pickofi's separately operated by the rudder and aileron trim knobs and jointly operated by the coordinated turn knob, the separate rudder and aileron follow-up systems and the difierential gear trains permitting the independent operations of the air pick-offs by such control knobs and follow-up systems; and

Figure 2 is a view in section taken along line 22 of Figure 1 showing the aileron air pick-off and gear operating means, the rudder air pick-off and operating means being the same.

Referring more particularly to the drawings, the rudder l is operated in either direction by cables 2 that extends about pulleys 3 and 4 connected to piston rods 5 and 6 of the usual piston of a hydraulic servo unit 1. The hydraulic system includes pressure oil pump 8 with lines 3 and ll] leading to the usual balanced oil valve l! which is actuated by a shaft l2 in either direction by the flexible diaphragm of the usual air relay IS, the oil lines from the balanced oil valve to either side of the servo piston being shown at M and iii. Likewise the airplane aileron I6 is operated in either direction by cables ll passing about pulleys l8 and i9 attached to piston rods 23 and 2| of the piston of the usual hydraulic servo unit 22. The hydraulic system also includes the usual balanced oil valve 23 with lines 24 and 25 leading to the same single oil pump '8 which also supplies rudder oil valve ll. Lines 26 and 21 lead from oil valve 23 to either side of the piston of servo 22. Oil valve 23 is operated in either direction by a shaft 23 connected to the flexible diaphragm of the usual air relay 29.

The pneumatic system of the rudder and aileron controls may include a single vacuum pump 3!! for evacuating the gyro box to permit in-rushing air to spin the gyro wheel 3! by means to be later described. In circuit with vacuum pump 30 through pipe 32, shown broken away, are both the rudder and aileron pneumatic control systems. For instance, air tubes 33 and 34 extend from opposite sides of the diaphragm of the rudder air relay l3 to the rudder air pick-off assembly, generally indicated at 35 in Figure 1, while air tubes 36 and 31 lead from tubes 33 and 34 to tube 32. Likewise in the aileron pneumatic system air tubes 38 and 39 lead from opposite sides of the diaphragm of air relay 29 to the aileron air pick-off assembly, generally indicated in Figure l at 43, while air tubes 4| and 42 connect tubes 38 and 33 to tube 32.

The two air pick-off assemblies 35 and 40 are the same and are operated in the same manner, the aileron pick-off being shown in Figure 2 to include an air pick-off bracket 40 to support air tubes 38 and 39 whose adjacent ends are normally open to the atmosphere to admit in-rushing air as the gyro box is being evacuated by vacuum pump 30. The means for valving this in-rushing air through the open ends of tubes 38 and 33 comprises a rotatably mounted shroud 42 which is shown in neutral with both tubes 38 and 39 open but which when rotated partially or completely closes one tube While partially or completely opening the other tube. Valve 40 is rigid with a gear 43 meshing with a gear 44 carried by a shaft 45 having a bevel gear 46 that meshes with a bevel gear 41 of a differential gear assembly. This may include a bevel gear 48 rigid with bevel gear 4'! and loosely mounted on shaft 49 which has fixed thereto a bevel gear 59. The aileron. trim. knob .5 I rotates-yaeshaft-52 .which is rigid withpiniongears 53 and 54 that mesh with bevel gears 48 and 50. The aileron follow-up system includes a cable 55 passing about pulley 56 and about the follow-up pulley 51 to rotate shaft 58 carrying a bevel gear 59 meshing with-a bevel gear 69 to rotate shaft 49 in either direction. Likewise there is provided a. rudder trim knobzfil having a shaft 62 rigid with differential pinion gears 63 and 64 which meshzwith'zbevelzgear165 rigid with bevel gear 96 meshing with bevel gear 6! on shaft 68 to rotate gear .69 meshing with gear 10 to rotate the shroud of rudder pick-off 35, in the same manner as the aileron .pick-oif shroud as shown in Figure 2, to regulate the clos- .ing and opening of tubes 33 and.-3 l to iii-rushing .air. Gears 65 and-66 maybe loose on shaft H :which is rigid with bevel gear 72. Shaft H car- .ries a bevel gear 72 meshing with bevel gear 13 .rigid with shaft 'l lrotating with the rudder:fo1- .low-up pulley '15 to whichis secured the followup cable-.16 extending'aboutpulley H to the rudzder cable 2.

The gyro rotor 3!, asiscustomary in an air .driven rotor is mounted in. the usual gyro box, .not shown, to be evacuated inthe usual manner .by/vacuum pump 39 to draw in high speed in- ,rushing air through a nozzle 78 to impinge on the .rotor buckets 19 to spin.the rotor on its pivots .80 and about an. axis normally coincidental with .the longitudinal axis of.the aircraft. Pivots-89 rotate in bearing assemblies 8 l and 82- in. gimbal frame 83 which-latter is mounted in a suitable stationary support (not shown) -.to be .constrained torotative movement-in a: single plane about an axis at right angles to the rotor axis .and transverse of the aircraftandindicated in .dotted lines .as A-A. As stated vbefore, the .-.ailern air pick-01f shroud-42 as well as thecorre- .sponding shroud of ;the ,rudder .air pickeofi shroud are both secured to the .gimbal-83.to be .moved jointly in either direction-as .thegimbal. is -moved relatively tothe. rotor spin-axis.

The above described construction-permits independent ,manual trim of the rudder .and .ailerons by knobs-6| .and to cause: rotation of gears 79 and .43 in either direction vtomove the rudder and aileronair pick-oifss35zand 49 with .respect to their shrouds. .It ;also permits or movement or these air pick-oil's. responsively; to .the two follow-upvsystems.

Such a constructionandarrangement lends .itself tobe adaptable for a'coordinated applica- .tion of rudder andaileron for a predetermined rate of turn. After rudder and aileron trimiit' is ,proposed to. initiate such a turn by. use vof-a single turn knob Mon a shaft.85 to rotateaworm. gear ;86 meshing with a ring geartfl'lfor rotating an .angle arm 88. This .armhasattached .thereto .an adjustable centralizing tension-coiLspring-89 .the other end of which is.attached topa-loopw9fl .fixed. to gimbalBB, ,the spring being ,of. predeterimined tensile strength. Thuaaturningnf knob 58.4 in either direction resiliently biases the.gimba1 .withrespect tothe, rotor spin-axis and awardingly .movesthe two shrouds-with respecttothe rudder andaileron.airpick-oiis to initiate ajoint application .of rudder andaileronfor a :predetermined rateofturn and atthe same .time perinitting the rudderand aileron followeup Systems to operate in the conventional manner to move the air pick-offs with respect to their shrouds.

As a matter of refinement there may also be provided a dash pot including a cylinder 9| in communication through a tube 92 to a box 93 with a suitable air bleedto be regulated by a control knob 94. The piston 95 of the dash pot has its piston rod 96 pivotally connected at 91. In this manner the movements of the gimbal relatively to the rotor spin axis may be effectively damped to an adjusted degree.

Additionally and for long period signals there .is. provided .-a gravity. operated pendulum 98 piv- .otally.suspendedat 99 and whose upper end is .5.-.formed in the-shape of a shroud I90 for regulat- ;ing..the.;air ,:pick off Illl and the entrance of .in-rushingair through tubes I02 and I03. These tubes are provided with air bleeds Hi4 and I05 .and. communicate with tubes 38 and 39 extending between the aileron air relay 29 and the aileron .air pick-.ofi-All.

.It is to be. understood thattheforegoing is. not a complete description of an automatic pilot, inasmuch .asnodisclosureis. made of the elevator .controlwhich is aseparate partof .the complete automatic pilot.

In. summary, the .gyro rotor. .spin :axisis coin- .cidental .with. the aircraft longitudinal axis. and ;.the pivot. axis of the gimbalis.transversethereto.

3O Rudder. trim. is ,mechanically.efiectedlby ..control knobs! and aileron trim by knob 5|.

Insofar as i, the ,gyro itself is concer.ned, it is responsive .only'to ,yaw, or vturn,and.is notre- .sponsiveto roll ..=or .pitch. When .the aircraft .yaws, or turns, from. a -set..course the gyro pre- .cesses and ...a signal .is ,given simultaneously vto the rudder. pick-.off .35 and the .aileronpick-off .40 to simultaneously .apply .counter rudder and :aileron.

When theaircraftrolls fromi-a set course the .gyro, havingits spinaxis coincidental With-the longitudinal axis. of the aircraft. and its .gimbal axis. transverse thereto, 2 is not .efiected. and per- .forms no function. infighting theaircraft to its .set course. However, when suchroll occurs, the pendulums98, being pivoted onantaxis 99.coin- :cidental with the longitudinal axisottheair- .craft, operatespick-ofi .190 to effect counter aileron. control.

Also, inasmuch as the gyrospin axis iscoincidental with .thelongitudinali axis. of .the aircraft ,and .the gimbalaxis. transversetheretq. and since .thegyro. is restrained by spring .39. it is not materially. .afiected. by..pitch. of .the aircraft from .a set courseiand has. no reflect on. either. the .aileron. vor .rudderservdsystems.

The rudder and aileron trim having beenaccomplishedby knobs -61. and 5 I respectively, a set course of combined rudderandaileromior proper non-skidding aerial maneuver; is set. through the gyro by .control knob. 84.

From. the foregoing. it will vbe seen that there has been provided .atsimple'and-effective auto- ,maticbank and-turn control-systememployinga .single constrained gyro and .a single. control knob for setting-a joint rudder. and. ail eron. application ,for .a predetermined rate .of .turn -after independent rudder and ailerontrim wh-ile permitting .the operationpfthe: rudder andaileron follow-up systems in the desired manne It;is,. of-course, to be understood that .the .system..described- .as applied to theconventional pneumatic-hydraulic automatic pilot-is equally applicable toan. automatic pilotwherein theggyro-roton is hydraulically .or-.electr ically.-driven. I I

I claim:

1. In an automatic pilot for an aircraft havin a rudder and aileron, servos for driving said rudder and aileron, a single gyro and a single axis gimbal therefor to constrain the gyro to one degree of freedom, a rudder pick-01f and an aileron pick-off mounted on said gimbal axis to be operated by said gimbal in its single plane movements, separate manual means for operating each of said pick-offs for aileron and rudder trim independently of each other and said gimbal and separate means for adjusting said gimbal to jointly operate both of said 'pick-oifs to jointly energize both of said servos to initiate a combined rudder and aileron operation for effecting a predetermined rate of turn.

2. In an automatic pilot for an aircraft having a rudder and an aileron, servos for driving said rudder and aileron, a single gyro and a single axis gimbal therefor to constrain the gyro to one degree of freedom, resilient means for biasing the single gimbal, a rudder pick-off and an aileron pick-01f mounted on said gimbal axis to be operated by said gimbal in its movements, separate manual means for operating each of said pick-offs for aileron and rudder trim independently of each other and said gimbal and separate means for adjusting said gimbal through said resilient biasing means to jointly operate both of said pick-offs to jointly energize both of said servos to initiate a combined rudder and aileron operation for effecting a predetermined rate of turn.

3. In an automatic pilot for an aircraft having a rudder and an aileron, servos for driving said rudder and aileron, a single gyro and a single axis gimbal therefor to constrain the gyro to one degree of freedom, a rudder pick-01 and an aileron pick-01f mounted on said gimbal axis to be operated by said gimbal in its single plane movements, separate manual control means for operating each of said pick-oifs for aileron and rudder trim independently of each other and said gimbal and separate means for adjusting said gimbal to jointly operate both of said pickoffs to jointly energize both of said servos to initiate a combined rudder and aileron operation for effecting a predetermined rate of turn, and rudder and aileron follow-up systems for operating said aileron pick-off and said rudder pick-off independently of each other and independently of the manual control means for independent operation of the pick-offs and independently of the manual control means for combined operation thereof.

4. In an automatic pilot for an aircraft having a rudder and an aileron, servos for driving said rudder and said aileron, a single gyro and a single axis gimbal therefor to constrain the gyro to one degree of freedom, a rudder pick-off and an aileron pick-off mounted on said gimbal axis to be operated by said gimbal in its movements, separate manual control means for operating each of said pick-ofis for aileron and rudder trim independently of each other and said gimbal and separate manually operable means and spring means connecting the same with said gimbal for adjusting said gimbal to jointly operate both of said pick-offs to jointly energize both of said servos to initiate a combined rudder and aileron operation for effecting a predetermined rate of turn, and rudder and aileron follow-up systems for operating said aileron pick-off and said rudder pick-off independently of each other and independently of the manual control means for independent operation of the pick-offs and independently of the manual control means for combined operation thereof.

5. In an automatic pilot for an aircraft having a rudder and an aileron, servos for driving said rudder and said aileron, common power means for operating both of said servos and separate pick-ofis for controlling the flow of power from said power means to individually operate said rudder and aileron servos, a single gyro assembly including a gyro wheel mounted in a single axis gimbal that is mounted for one axis of rotation only, one element of each of said pick-offs being connected to said gimbal to be operated thereby about the axis of said gimbal and manual means for separate operation of each of the other pickoff elements for rudder and aileron trim respectively and a single manual control means for resiliently biasing said gimbal to jointly move the pick-off elements connected to said gimbal to jointly apply rudder and aileron control to set and control a predetermined rate of turn.

6. In an automatic pilot for an aircraft having a rudder and an aileron, servos for driving said rudder and aileron, common power means for operating both of said servos and separate pickoifs for controlling the flow of power from said power means to individually operate said rudder and aileron servos, a single gyro assembly including a gyro wheel mounted in a gimbal that is mounted for one axis of rotation only, one element of each of said pick-ofis being connected to said gimbal to be operated thereby about the axis of said gimbal and manual means for separate operation of each of the other pick-off elements for rudder and aileron trim respectively, a rudder follow-up system and an aileron followup system for separately operating said lastnamed pick-off elements and a differential gear train between each of said manual trim controls and corresponding follow-up systems so that the rudder and aileron manual trim controls may be operated independently of the follow-up systems, and a single manual control means for resiliently biasing said gimbal to jointly move the pick-off elements connected to said gimbal to jointly apply rudder and aileron control to set and control a predetermined rate of turn.

7. In an automatic pilot for an aircraft having a rudder and an aileron, servos for driving said rudder and aileron, common power means for operating both of said servos and separate pickofis for controlling the flow of power from said power means to individually operate said rudder and aileron servos, a single gyro assembly including a gyro wheel mounted in a gimbal mounted for one axis of rotation only, one element of each of said pick-offs being connected to said gimbal to be operated thereby about the axis of said gimbal and manual means for separate operation of each of the other pick-off elements for rudder and aileron trim respectively, and a single manual control means for resiliently biasing said gimbal to jointly move the pick-off elements connected to said gimbal to jointly apply rudder and aileron control to set and control a predetermined rate of turn.

8. In an automatic pilot for an aircraft having a rudder and an aileron, servos for driving said rudder and aileron, common power means for operating both of said servos and separate pickoifs for controlling the flow of power to said power means to individually operate said rudder and aileron servos, a single gyro assembly including a gyro wheel mounted in a gimbal that is mounted for one axis of rotation only, one element of eachof saidzpick-c-offs. being connected. to said gimbal to be operated thereby about the axis of said gimbal and manual means for separate operation oi each of the other pick-ofi elements for rudder and aileron trim respectively, a rudder follow-up systemand an aileron followupsystem for respectively and separately operatingsaid last-named-pick-off elements independently of manual operation thereof, and a single manual controlmeans for resiliently biasing said gimbal to jointly move the pick-01f elements connested to said gimbal to jointly apply rudder and aileron control to set and control a predetermined rate of turn.

9. In an automatic pilot for an aircraft having a rudder and an aileron, servos for driving said rudder and aileron, common power means for operating both of said servos and separate pickoffs-for controllin the flow of power to said power means to individually operate said rudder and aileron serves, a single gyro assembly including a, gyro wheel mounted in a single gimbal, mounted for one axis of rotation only,lone element of each of said pick-ofis being connected to said gimbal to be operated thereby about the axis of 25 said gimbal and manual means for separate operation of each of the other pick-off elements for rudder and aileron trim respectively, a rudder follow-up system and an-aileron follow-up system for respectively and. separately operating. said lastnamed picksoff'elements and a diiferential gear train between eachhof sai'dlmanual trim controls and the corresponding-followup systems so that the rudder and aileron manual trim controls may be operated independently of the follow-up systems, and a single manual control means for resiliently biasing said. gimbal to jointly move the pick-01f elements connected to said gimbal to jointly apply rudder and aileron control to set and control a. predetermined rate of turn.

CARL G. NYMAN.

REFERENCES. CITED The following references are of record in the fileof this patent:

UNITED STATES PATENTS Number Name Date 1,825,994 Cooke- 0st; 6, 1931 1,992,086 Meredith et a1 Feb. 19, I935 2,066,194 Bates- Dec. 29; 1936 2,199,256 De- Florea Apr. 30, 1940 2,325,108 Carlson l July 27', 1943 

